A TTL timer project of yore

[Viktor] just pulled out another one of his decades-old projects. This time around it’s a timer he built using 7400 logic chips. It was a great way for him to learn about electronics, and ended up serving as his alarm clock every morning.

Two pieces of copper clad board were cut to the same size. One of them was etched to act as the circuit board. The other was outfitted as a face plate. The same type of transfer sheets used to mask the traces of the circuit were also used to apply labels to the face plate. It was then coated with acrylic spray to protect it and stave off corrosion. The clock keeps time based on a half-wave rectified signal. The source is from a transformer which steps mains voltage down to a safe level for the 7805 regulator that supplies the clock’s power bus.

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6 thoughts on “A TTL timer project of yore”

I’m loving the fallout pitena of the built. age has done well for it in at least astetics. its like what you expect an eleivator face plate to be in close to 50-100 years. on the opposite side of the coin very interesting build with the psudo anolog led component. would be very FFVII by now if he used some vixe tubes =P

I expect the lettering was done with the dry transfer approach. I haven’t seen it in years, but there used to be sheets of different sizes and fonts of letters and numbers which would be transferred to the surface with just a little pressure. Afterwards, a spray of clear krylon would protect the lettering.